PROGRESSIVE SUSPENSION KIT FST MONOT FORK STD 31-4006 31-4006Converts dual damper rod forks to high performance cartridge forks, Contains high performance, gas charged monotube fork cartridges and custom tuned fork springs, Improves resistance to front brake dive, front end stability, cornering and bottoming control, No modification for forks required, Lowering kits lower the front end up to 2", Made in the U. S. A, Lowering kits are not for use on LOW models.